High frequency electron discharge device



United States Patent HIGH FREQUENCY ELECTRON DISCHARGE DEVICE Arthur C.Stacker, Collingswood, N.J., assignor to the United States of America asrepresented by the Secretary of the Air Force Application June 20, 1957,Serial No. 667,060

12 Claims. (Cl. 31544) This invention relates to very high frequencyelectron discharge devices, and more particularly to a coaxialtransmission line assembly for such a device.

One object of the invention is to reduce the magnitude of mechanicalstress and strain imposed upon an electron discharge device incident toits insertion and withdrawal in a coaxial transmission line assembly.

Another object of this invention is to provide an improved coaxialtransmission line assembly whereinthe associated high frequency electrondischarge device may be inserted and withdrawn without disturbing theremainder of the assembly.

A further object of the invention is to provide a simple tuningstructure for a coaxial line assembly utilizing an electron dischargedevice wherein the anode blocking capacitor for the said device may beremoved without disturbing the associatedcoaxial transmission line.

Another object of this invention is to provide a coaxial transmissionline assembly aifording isolation for the anode element of the electrondischarge device so that the reception by said anode element of the DC.voltage developed in said device, produces no reactive effects along anyassociated conductive elements of the aforesaid assembly.

Transmitters and receivers in the very high frequency range frequentlyuse electron discharge devices in the socalled grounded grid circuitwherein the grid is the electron discharge element common to both' inputand output circuits, the input signal being applied between grid andcathode and the output signal being removed between grid and anode. Inthe high frequency range it is also common practice to use resonantcoaxial transmission lines astuned circuits.

Coaxial transmission line assemblies, as heretofore known, have variousdisadvantages. In one assembly the anode line is constructed around theoutside ofa cathode line. In such an assembly the high voltage isexposedand-it is difficult to provide RF. and power connectionsto. thetuned circuits. In other arrangements it is necessarytoremove one of thecoaxial lines in order to insert orwithdraw the electron dischargedevice associated therewith.

The present invention provides unitary, interlocking means associatedwith a resonant coaxial transmission line'in such a manner as to permitinsertion and withdrawal of an electrondischarge device therethrough.The said unitary means includes a carrier to transmit the mechanicalstress and strain incident to insertion and withdrawal, the carrierbeing left in place while the electron discharge device is operating inthe coaxial line assembly.

To permit operating the exposed end of the carrier with direct currentat zero potential, the anode blocking capacitor is built into the lowerend of the carrier. The electron discharge device is mountedin thecarrier and then inserted into the coaxial line assembly. The R.F.component of anode current passes through the anode ice capacitor to theoutside surface of the carrier and then to the center conductor of theaforesaid assembly.

For a better understanding of the invention, together with other andfurther objects, advantages and capabilities thereof, reference is madeto the following description of the embodiment illustrated in the singlefigure of the accompanying drawing, which is a longitudinal sectionalview of a resonant coaxial transmission line assembly embodying theinvention.

The resonant coaxial transmission line is comprised of a pair ofcylindrical cavity resonators 1 and 2 respectively, for electronicdischarge tube 3 which is utilized in a grounded grid circuit whereingrid 4 of electron discharge device 3 is common to both input and outputcircuits. The input being applied between grid 4 and cathode 8 andoutput being removed between grid 4 and anode 6. Resonator 1 is utilizedas a resonator for grid 4 and cathode 8 of device 3 and resonator 2utilized as a resonator for grid 4 and anode 6.

Resonator 1 is comprised of outer conductive cylinders 7 and innerconductive cylinder 8, respectively. The terminating end of resonator 1is short-circuited by adjustable annular'piston 9. The other terminatingend of resonator 1 is completed by means of annular conductive disc 10.Annular conductive disc 11 has a plurality of conductive fingers 12contacting grid flange 4 which is separated from annular disc 10 byannular dielectric disc 13, thus forming a capacitor. The R.F. energyfrom grid. 4 is thereby coupled to outer conductive cylinder 7. Cathode5 is capacitively coupled to inner conductive cylinder 8 by means ofannular conductive disc 14, annular dielectric disc 15 and annularconductive disc 16 having a. plurality of conductive fingers contactingcathode flange S. Outer cylinder 7 is electrically connected to innercylinder 8 by adjustable annular shorting piston 9.- Cylinders 7 and 8are heldin concentric mechanical inter-relationship by annular discshaped end member 17 and disc 22 performs the same function as betweenelements 20 and 21. Direct current connection. to grid 4 is completed byway of wire 18- and to cathode 5 by way of wire 19.

Resonator 2 is comprised of outer conductive cylinder 20 and innerconductive cylinder 21 which are electrically interconnected by way ofadjustable annular shorting piston 23. The other terminating end iscommon to both resonator 1 and 2 and is annular conductive disc 10. Grid4 is capacitively coupled to outer cylinder 20 by way of annularconductive disc 10, annular dielectric disc 13 and annular conductivedisc 11 having a plurality of conductive fingers 12 contacting theaforementioned-v grid 4. Inner conductive cylinder 21 is made ofsuflicient diameter so that it permits the insertion and withdrawalof acarrier with electron discharge device rigidly mounted at one end. Thecarrier is comprised of two concentric conductive cylinders 24 and 25 ofwhich the outer cylinder 24 extends axially beyond the plane ofterminating disc 22 while the inner cylinder '25 terminates in athreaded portion 27 adapted to receive a fitting 28 serving tomechanically seecure anode flange of electron discharge device 3 inadjustable relation thereto, there beingan inner shoulder 29 formedinternally of cylinder 25 to cooperate with fitting 28 in this securingoperation. Resonator 2 also includes cooling air duct 32 to providemeans to dissipate heat from discharge device 3.

In order to establish the desired capacitancerelation ship between thecylinders 24 and 25 a dielectric material, such as sheet mica or itsequivalent, is wrapped about the outer periphery of cylinder 25 asindicated at cylinder 25 and the inner surface of cylinder 24 thuseffecting a unitary organization consisting of the two cylinders 2425and the interposed dielectric material 30. To further insure maintenanceof the components of this assembly in the indicated relationships theremay be included a multi-fingered conducting ring 31 depending from thelower portion of the inner wall 21 of the resonator 2, said ring 31having its lower portion turned inwardly to engage and exert an inwardlydirected clamping pressure upon the assembly 24-3025.

It will thus be seen the aforesaid carrier has provided a mounting forelectron discharge device 3, it also provides means for insertion andwithdrawal of electron discharge device 3 into aforesaid coaxial lineassembly. In addition the anode blocking capacitor is built into thelower end of said carrier. The DC. path from anode 6 is completed by aninsulated conductive cylinder 25 to wire 33. When electron dischargedevice 3 and said associated carrier are inserted, the RF. component ofanode current passes through the said capacitor to the outside surfaceof conductive cylinder 24 and thence by contact fingers 31 to theoutside surface of inner conductive cylinder 21, thereby forming theelectrical circuit for resonator 2.

While there has been shown and described a preferred embodiment of thepresent invention, it will become obvious to those skilled in the artthat various changes and modifications may be made therein withoutdeparting from the invention as defined by the appended claims.

What is claimed is:

1. In combination with an electron discharge tube, a coaxial cylindricaltransmission line operatively associated with said tube, saidtransmission line including an assembly of elements concentricallysurrounding said electron discharge tube, and a tube carrying assemblyintegrated with said electron discharge tube and extending axially ofsaid transmission line assembly to a point beyond the outer limits ofsaid transmission line assembly to effect insertion and withdrawal ofsaid electron discharge tube with said tube carrying assembly from saidtransmission line assembly independently of any disturbance of saidtransmission line assembly.

2. The combination as set forth in claim 1 wherein said tube carryingassembly includes inner and outer concentric cylindrical conductors ofwhich one conductor extends axially beyond the said transmission lineassembly, and means for adjustably clamping the other conductor to saidelectron discharge tube.

3. The combination as set forth in claim 1 wherein said tube carryingassembly includes inner and outer concentric cylindrical conductors ofwhich one conductor extends axially beyond the said transmission lineassembly, means for adjustably clamping the other conductor to saidelectron discharge tube and a dielectric material positioned about theouter periphery of the inner conductor to interpose capacitance couplingbetween said electron discharge tube and said coaxial transmission lineassembly.

4. The combination as set forth in claim 1 wherein said tube carryingassembly includes inner and outer concentric cylindrical conductors ofwhich said outer conductor extends axially beyond the said transmissionline assembly, means for adjustably clamping said inner conductor tosaid electron discharge tube, means positioned about outer periphery ofsaid inner conductor to interpose capacitance coupling between saidelectron discharge tube and said coaxial transmission line assembly, andmeans constituted in part by said inner conductor for feeding directcurrent to the anode of said electron discharge tube.

5. In combination with an electron discharge tube, a pair of coaxialcavity resonators external to but operatively associated with said tube,means for coupling the input and output of said device to saidresonators, the first resonator being coupled between the grid andcathode of said tube, the second resonator between the grid and 4 anodeof said tube, the said pair of cavity resonators each including innerand outer conductors of which said inner conductor has an insidediameter larger than the outside diameter of said electron dischargetube to effect insertion and withdrawal of said electron discharge tubeby axial telescoping of said tube into and out of said inner conductor,and a tube carrying assembly integrated with said electron dischargetube to insert and withdraw the said electron discharge tube with saidintegrated tube carrying assembly into said combination of resonators byway of said inner conductor.

6. In combination with an electron discharge tube, a pair of coaxialcavity resonators external to but operatively associated with said tube,means for coupling the input and output of said tube to said resonators,the first resonator being coupled between the grid and cathode of saidtube, the second resonator between the grid and anode of said tube, thesaid pair of cavity resonators each including inner and outerconductors, and a tube carrier assembly interlocked with said electrondischarge tube to insert and withdraw the said electron discharge devicein unitary fashion with said tube carrying assembly independently ofsaid inner conductor of said second cavity resonator, said innerconductor of said second resonator having an inside diameter larger thanthe outside diameter of said tube carrying assembly in order to effectthe insertion and withdrawal of said electron discharge tube with saidtube carrying assembly by axial telescoping of said electron dischargetube with said tube carrying assembly into and out of said innerconductor.

7. In combination with an electron discharge tube, a pair of coaxialcavity resonators external to but operatively associated with said tube,means for coupling the input and output of said tube to said resonators,the first resonator being coupled between the grid and cathode of saidtube, the second resonator between the grid and anode of said tube, thesaid pair of cavity resonators each including a pair of concentric innerand outer cylindrical conductors, and a tube carrying assemblyintegrated with said electron discharge tube for insertion andwithdrawal of said electron discharge device into and out of said secondcavity resonator by way of said inner conductor of said second cavityresonator, said inner conductor having an inside diameter larger thanthe outside diameter of said tube carrying assembly to effect insertionand withdrawal of said electron discharge tube by axial telescoping ofsaid electron discharge tube integrated with said tube carrying assemblyinto said inner conductor.

8. The combination as set forth in claim 7 wherein the last-named meansincludes retention means for adjustably clamping the cavity resonator tosaid electron discharge tube.

9. The combination as set forth in claim 7 wherein said tube carryingassembly includes inner and outer concentric cylindrical conductors ofwhich said outer conductor extends axially beyond said second cavityresonator, means for adjustably clamping said inner conductor to saidelectron discharge tube, dielectric means positioned about the outerperiphery of said inner conductor to interpose capacitive couplingbetween said anode of said electron discharge tube and said outerconductor, and means for feeding direct current to said anode of saidelectron discharge tube by way of said inner conductor.

10. In combination with an electron discharge tube, a pair of coaxialcavity resonators external to but operatively associated with said tube,means for coupling the input and output of said tube to said resonators,the first resonator being coupled between the grid and cathode of saidtube, the second resonator between the grid and anode of said tube, thesaid pair of cavity resonators each including inner and outer conductorsand tube carrying assembly to insert and withdraw said electrondischarge tube by way of said second cavity resonator, said tubecarrying assembly including inner and outer concentric cylindricalconductors of which said outer concentric conductor extends axiallybeyond said second cavity resonator, means for adjustably clamping saidinner concentric conductor to said electron discharge tube, dielectricmeans positioned about outer periphery of said inner concentricconductor to interpose capacitance coupling between said electrondischarge tube and said second cavity resonator, and means constitutedin part by said inner concentric conductor for feeding direct current tothe anode of said electron discharge tube.

11. In combination with an electron discharge tube, a pair of coaxialcavity resonators external to and operatively associated with said tube,means for coupling the input and output of said tube to said resonators,the first resonator being coupled between the grid and cathode of saidtube, the second resonator between the grid and anode of said tube, thesaid pair of cavity resonators each including a pair of concentric innerand outer cylindrical conductors, tube carrying assembly for insertionand withdrawal of said eelctron discharge tube into said second cavityresonator by way of said inner conductor of said second cavityresonator, said tube carrying assembly including inner and outertelescopic cylindrical conductors of which said outer telescopicconductor extends axially beyond said cavity resonator upon completeinsertion into said cavity resonator, means for adjustably clamping saidinner telescopic conductor to said electron discharge tube, dielectricmeans positioned about the outer periphery of said inner telescopicconductor to interpose capacitance coupling between said electrondischarge tube and said outer telescopic conductor, means constituted inpart by said inner telescopic conductor for feeding direct current tothe anode of said electron discharge tube, and means attached to saidinner conductor of said second cavity resonator to direct an inwardclamping pressure against said tube carrying assembly upon insertioninto said inner conductor of said second cavity resonator.

12. An electron discharge tube carrying assembly comprising inner andouter concentric cylindrical conductors of which said outer conductorextends axially beyond said inner conductor, means for adjustablyclamping said inner conductor to said electron discharge tube,dielectric means positioned about the outer periphery of said innerconductor so that said inner and outer concentric conductors coact withsaid dielectric means to operate as a capacitor, and means for feedingdirect current to the anode of said electron discharge tube by way ofsaid inner conductor.

References Cited in the file of this patent UNITED STATES PATENTS2,472,721 'Nergaard June 7, 1949 2,530,836 Mumford Nov. 21, 19502,574,012 Bonne et a1. Nov. 6, 1951 2,589,246 Grimm Mar. 18, 19522,666,160 Bowie Ian. 12, 1954 2,752,524 Martin June 26, 1956 2,816,245Coeterier Dec. 10, 1957 2,828,438 McArthur Mar. 25, 1958 FOREIGN PATENTS658,747 Great Britain Oct. 10, 1951

